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Induced Chemical Defense of a Mushroom by a Double-Bond-Shifting Polyene Synthase |
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| Authors: | Philip Brandt Dr. María García-Altares Prof. Dr. Markus Nett Prof. Dr. Christian Hertweck Prof. Dr. Dirk Hoffmeister |
| Affiliation: | 1. Department Pharmaceutical Microbiology at the Hans Knöll Institute, Friedrich-Schiller-Universität, Winzerlaer Strasse 2, 07745 Jena, Germany;2. Department Biomolecular Chemistry, Leibniz Institute for Natural Product Research and Infection Biology, Beutenbergstrasse 11a, 07745 Jena, Germany;3. Department of Biochemical and Chemical Engineering, Technical University Dortmund, Emil-Figge-Strasse 66, 44227 Dortmund, Germany |
| Abstract: | The antilarval mushroom polyenes 18-methyl-19-oxoicosaoctaenoic acid and 20-methyl-21-oxodocosanonaenoic acid appear in response to injury of the mycelium of the stereaceous mushroom BY1. We identified a polyketide synthase (PPS1) which belongs to a hitherto completely uncharacterized clade of polyketide synthases. Expression of the PPS1 gene is massively upregulated following mycelial damage. The synthesis of the above polyenes was reconstituted in the mold Aspergillus niger as a heterologous host. This demonstrates that PPS1 1) synchronously produces branched-chain polyketides of varied lengths, and 2) catalyzes the unprecedented shift of eight or nine double bonds. This study represents the first characterization of a reducing polyketide synthase from a mushroom. We also show that injury-induced de novo synthesis of polyketides is a fungal response strategy. |
| Keywords: | biosynthesis fungus natural products polyenes polyketide |